Hybrid calculation of hadronic vacuum polarization in muon g-2 to 0.48\%

TL;DR

This paper reports a new lattice QCD calculation of the leading order hadronic vacuum polarization contribution to the muon g-2, achieving high precision and validating the Standard Model within 0.5 standard deviations.

Contribution

The study improves the precision of the lattice QCD calculation of the muon g-2 contribution by a factor of 1.6 and includes experimental input for better accuracy.

Findings

Reduced uncertainties in the calculation by a factor of 1.6.

Predicted muon g-2 contribution differs from experimental measurement by only 0.5 standard deviations.

Validation of the Standard Model to 11 digits.

Abstract

We present a new lattice QCD calculation of the leading order hadronic vacuum polarization (LO-HVP) contribution to the muon anomalous magnetic moment $a_\mu$. We reduce uncertainties compared to our earlier computation arXiv:2002.12347 by a factor of 1.6. We perform simulations on finer lattices allowing for an even more accurate continuum extrapolation. We also include a small, long-distance contribution obtained using input from experiments in a low-energy regime where they all agree. Combined with other standard model contributions our result, $a_\mu^{LO-HVP}=715.1(2.5)(2.3)[3.4] \times 10^{-10}$, leads to a prediction that differs from the recent measurement of $a_\mu$ by only 0.5 standard deviations. This provides a remarkable validation of the standard model to 11 digits.